<p>Antipsychotic drugs (or neuroleptics) are a large class of drugs which can be divided into three groups: phenothiazine, miscellaneous and atypical (Box 1). They are used to tranquillise patients without impairing consciousness and without causing paradoxical excitement. They are often referred to as major tranquillisers but this is misleading since these drugs also relieve florid psychotic symptoms such as thought disorder, hallucinations and delusions, and prevent relapse.</p>